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  1. 01 12月, 2015 6 次提交
  3. 26 11月, 2015 3 次提交
  5. 28 10月, 2015 12 次提交
  7. 23 10月, 2015 1 次提交
    • S
      powerpc/85xx: Load all early TLB entries at once · d9e1831a
      由 Scott Wood 提交于 
      Use an AS=1 trampoline TLB entry to allow all normal TLB1 entries to
be loaded at once.  This avoids the need to keep the translation that
code is executing from in the same TLB entry in the final TLB
configuration as during early boot, which in turn is helpful for
relocatable kernels (e.g. kdump) where the kernel is not running from
what would be the first TLB entry.

On e6500, we limit map_mem_in_cams() to the primary hwthread of a
core (the boot cpu is always considered primary, as a kdump kernel
can be entered on any cpu).  Each TLB only needs to be set up once,
and when we do, we don't want another thread to be running when we
create a temporary trampoline TLB1 entry.
Signed-off-by: NScott Wood <scottwood@freescale.com>
      d9e1831a
  9. 22 10月, 2015 1 次提交
    • V
      powerpc/rtas: Validate rtas.entry before calling enter_rtas() · 8832317f
      由 Vasant Hegde 提交于 
      Currently we do not validate rtas.entry before calling enter_rtas(). This
leads to a kernel oops when user space calls rtas system call on a powernv
platform (see below). This patch adds code to validate rtas.entry before
making enter_rtas() call.

  Oops: Exception in kernel mode, sig: 4 [#1]
  SMP NR_CPUS=1024 NUMA PowerNV
  task: c000000004294b80 ti: c0000007e1a78000 task.ti: c0000007e1a78000
  NIP: 0000000000000000 LR: 0000000000009c14 CTR: c000000000423140
  REGS: c0000007e1a7b920 TRAP: 0e40   Not tainted  (3.18.17-340.el7_1.pkvm3_1_0.2400.1.ppc64le)
  MSR: 1000000000081000 <HV,ME>  CR: 00000000  XER: 00000000
  CFAR: c000000000009c0c SOFTE: 0
  NIP [0000000000000000]           (null)
  LR [0000000000009c14] 0x9c14
  Call Trace:
  [c0000007e1a7bba0] [c00000000041a7f4] avc_has_perm_noaudit+0x54/0x110 (unreliable)
  [c0000007e1a7bd80] [c00000000002ddc0] ppc_rtas+0x150/0x2d0
  [c0000007e1a7be30] [c000000000009358] syscall_exit+0x0/0x98

Cc: stable@vger.kernel.org # v3.2+
Fixes: 55190f88 ("powerpc: Add skeleton PowerNV platform")
Reported-by: NNAGESWARA R. SASTRY <nasastry@in.ibm.com>
Signed-off-by: NVasant Hegde <hegdevasant@linux.vnet.ibm.com>
[mpe: Reword change log, trim oops, and add stable + fixes]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      8832317f
  11. 21 10月, 2015 5 次提交
    • G
      powerpc/eeh: More relaxed condition for enabled IO path · 872ee2d6
      由 Gavin Shan 提交于 
      When one or both of the below two flags are marked in the PE state, the
PE's IO path is regarded as enabled: EEH_STATE_MMIO_ACTIVE or
EEH_STATE_MMIO_ENABLED.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      872ee2d6
    • G
      powerpc/eeh: Force reset on fenced PHB · 8234fced
      由 Gavin Shan 提交于 
      On fenced PHB, the error handlers in the drivers of its subordinate
devices could return PCI_ERS_RESULT_CAN_RECOVER, indicating no reset
will be issued during the recovery. It's conflicting with the fact
that fenced PHB won't be recovered without reset.

This limits the return value from the error handlers in the drivers
of the fenced PHB's subordinate devices to PCI_ERS_RESULT_NEED_NONE
or PCI_ERS_RESULT_NEED_RESET, to ensure reset will be issued during
recovery.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: NDaniel Axtens <dja@axtens.net>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      8234fced
    • G
      powerpc/eeh: More relaxed hotplug criterion · f2da4ccf
      由 Gavin Shan 提交于 
      Currently, we rely on the existence of struct pci_driver::err_handler
to decide if the corresponding PCI device should be unplugged during
EEH recovery (partially hotplug case). However that check is not
sufficient. Some device drivers implement only some of the EEH error
handlers to collect diag-data. That means the driver still expects a
hotplug to recover from the EEH error.

This makes the hotplug criterion more relaxed: if the device driver
doesn't provide all necessary EEH error handlers, it will experience
hotplug during EEH recovery.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
[mpe: Minor change log rewording]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      f2da4ccf
    • G
      powerpc/eeh: Don't unfreeze PHB PE after reset · 527d10ef
      由 Gavin Shan 提交于 
      On PowerNV platform, the PE is kept in frozen state until the PE
reset is completed to avoid recursive EEH error caused by MMIO
access during the period of EEH reset. The PE's frozen state is
cleared after BARs of PCI device included in the PE are restored
and enabled. However, we needn't clear the frozen state for PHB PE
explicitly at this point as there is no real PE for PHB PE. As the
PHB PE is always binding with PE#0, we actually clear PE#0, which
is wrong. It doesn't incur any problem though.

This checks if the PE is PHB PE and doesn't clear the frozen state
if it is.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      527d10ef
    • C
      powerpc/prom: Avoid reference to potentially freed memory · 1856f50c
      由 Christophe Jaillet 提交于 
      of_get_property() is used inside the loop, but then the reference to the
node is dropped before dereferencing the prop pointer, which could by then
point to junk if the node has been freed.

Instead use of_property_read_u32() to actually read the property
value before dropping the reference.

of_property_read_u32() requires at least one cell (u32) to be present,
which is stricter than the old logic which would happily dereference a
property of any size. However we believe all device trees in the wild
have at least one cell.

Skiboot may produce memory nodes with more than one cell, but that is
OK, of_property_read_u32() will return the first one.
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
[mpe: Expand change log with device tree details]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      1856f50c
  13. 19 10月, 2015 3 次提交
  15. 15 10月, 2015 3 次提交
  17. 12 10月, 2015 1 次提交
    • A
      powerpc/mm: Differentiate between hugetlb and THP during page walk · 891121e6
      由 Aneesh Kumar K.V 提交于 
      We need to properly identify whether a hugepage is an explicit or
a transparent hugepage in follow_huge_addr(). We used to depend
on hugepage shift argument to do that. But in some case that can
result in wrong results. For ex:

On finding a transparent hugepage we set hugepage shift to PMD_SHIFT.
But we can end up clearing the thp pte, via pmdp_huge_get_and_clear.
We do prevent reusing the pfn page via the usage of
kick_all_cpus_sync(). But that happens after we updated the pte to 0.
Hence in follow_huge_addr() we can find hugepage shift set, but transparent
huge page check fail for a thp pte.

NOTE: We fixed a variant of this race against thp split in commit
691e95fd
("powerpc/mm/thp: Make page table walk safe against thp split/collapse")

Without this patch, we may hit the BUG_ON(flags & FOLL_GET) in
follow_page_mask occasionally.

In the long term, we may want to switch ppc64 64k page size config to
enable CONFIG_ARCH_WANT_GENERAL_HUGETLB
Reported-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      891121e6
  19. 02 10月, 2015 2 次提交
  21. 01 10月, 2015 2 次提交
    • M
      powerpc/vdso: Avoid link stack corruption in __get_datapage() · c974809a
      由 Michael Neuling 提交于 
      powerpc has a link register (lr) used for calling functions. We "bl
<func>" to call a function, and "blr" to return back to the call site.

The lr is only a single register, so if we call another function from
inside this function (ie. nested calls), software must save away the
lr on the software stack before calling the new function. Before
returning (ie. before the "blr"), the lr is restored by software from
the software stack.

This makes branch prediction quite difficult for the processor as it
will only know the branch target just before the "blr".

To help with this, modern powerpc processors keep a (non-architected)
hardware stack of lr called a "link stack". When a "bl <func>" is
run, the lr is pushed onto this stack. When a "blr" is called, the
branch predictor pops the lr value from the top of the link stack, and
uses it to predict the branch target. Hence the processor pipeline
knows a lot earlier the branch target.

This works great but there are some cases where you call "bl" but
without a matching "blr". Once such case is when trying to determine
the program counter (which can't be read directly). Here you "bl+4;
mflr" to get the program counter. If you do this, the link stack will
get out of sync with reality, causing the branch predictor to
mis-predict subsequent function returns.

To avoid this, modern micro-architectures have a special case of bl.
Using the form "bcl 20,31,+4", ensures the processor doesn't push to
the link stack.

The 32 and 64 bit variants of __get_datapage() use a "bl; mflr" to
determine the loaded address of the VDSO. The current versions of
these attempt to use this special bl variant.

Unfortunately they use +8 rather than the required +4. Hence the
current code results in the link stack getting out of sync with
reality and hence the resulting performance degradation.

This patch moves it to bcl+4 by moving __kernel_datapage_offset out of
__get_datapage().

With this patch, running a gettimeofday() (which uses
__get_datapage()) microbenchmark we get a decent bump in performance
on POWER7/8.

For the benchmark in tools/testing/selftests/powerpc/benchmarks/gettimeofday.c
  POWER8:
    64bit gets ~4% improvement
    32bit gets ~9% improvement
  POWER7:
    64bit gets ~7% improvement
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Reported-by: NAaron Sawdey <sawdey@us.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      c974809a
    • M
      powerpc/vdso: Emit GNU & SysV hashes · 787b393c
      由 Michael Ellerman 提交于 
      Andy Lutomirski says:

  Some dynamic loaders may be slightly faster if a GNU hash is
  available.

  This is unlikely to have any measurable effect on the time it takes
  to resolve vdso symbols (since there are so few of them).  In some
  contexts, it can be a win for a different reason: if every DSO has a
  GNU hash section, then libc can avoid calculating SysV hashes at
  all. Both musl and glibc appear to have this optimization.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      787b393c
  23. 17 9月, 2015 1 次提交